Many components of internal combustion engine systems are subjected to relatively high temperatures during operation. In some instances, without some dedicated means for cooling engine system components, operation of the engine system may be sub-optimal, or even compromised altogether. Certain fuel system components commonly used in internal combustion engines are one notable example where cooling may be desired. It is common for fuel injectors used in internal combustion engines to utilize relatively fast moving control valves, actuators and the like to control fuel injection into an associated engine cylinder. The relatively rapid actuation of electrical actuators commonly used in fuel injectors can generate heat, which in combination with heat generated by the engine itself, can raise the temperature of the actuator and associated components above desired levels.
In recent years, piezoelectric actuators have been increasingly used to actuate fuel injector components. Piezoelectric actuators typically consist of a piezoelectric element which changes conformation, typically by lengthening in response to application of an electrical potential. Conventional systems employ a piezoelectric actuator which relatively rapidly lengthens and shortens to control the position of a control valve, which is in turn responsible for controlling a timing of fuel injection. As a piezoelectric element cycles between an excited state and an unexcited state, it tends to generate a relatively large amount of heat. Where piezoelectric actuators are used, problems attendant to cooling may be particularly acute.
U.S. Pat. No. 4,553,059 to Abe et al. is directed to a cooling strategy for a piezoelectric actuator. In the design proposed by Abe et al., a piezoelectric actuator includes a housing wherein a piezoelectric element is disposed. The piezoelectric element is positioned within an enclosure, having a thermally conductive material in contact with the piezoelectric element. A cooling liquid is circulated through a space surrounding the enclosure, and is stated to absorb heat from the piezoelectric element which is transferred through the thermally conductive material. While the design in Abe et al. may have applicability in certain environments, the fluid connections necessary to supply and drain cooling fluid are relatively complex. Moreover, assembly and proper positioning of the piezoelectric actuator of Abe et al. may be cumbersome in an engine environment.